A communication infrastructure is an essential part to the success of the emerging smart grid. A scalable and pervasive communication infrastructure is crucial in both construction and operation of a smart grid. In this paper, we present the background and motivation of communication infrastructures in smart grid systems. We also summarize major requirements that smart grid communications must meet. From the experience of several industrial trials on smart grid with communication infrastructures, we expect that the traditional carbon fuel based power plants can cooperate with emerging distributed renewable energy such as wind, solar, etc, to reduce the carbon fuel consumption and consequent green house gas such as carbon dioxide emission. The consumers can minimize their expense on energy by adjusting their intelligent home appliance operations to avoid the peak hours and utilize the renewable energy instead. We further explore the challenges for a communication infrastructure as the part of a complex smart grid system. Since a smart grid system might have over millions of consumers and devices, the demand of its reliability and security is extremely critical. Through a communication infrastructure, a smart grid can improve power reliability and quality to eliminate electricity blackout. Security is a challenging issue since the on-going smart grid systems facing increasing vulnerabilities as more and more automation, remote monitoring/controlling and supervision entities are interconnected.

https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1315&context=electricalengineeringfacpub

A Survey on Smart Grid CommunicationInfrastructures: Motivations, Requirements andChallenges

Most ultrawideband (UWB) location systems already proposed for position estimation have only been individually evaluated for particular scenarios. For a fair performance comparison among different solutions, a common evaluation scenario would be desirable. In this paper, we compare three commercially available UWB systems (Ubisense, BeSpoon, and DecaWave) under the same experimental conditions, in order to do a critical performance analysis. We include the characterization of the quality of the estimated tag-to-sensor distances in an indoor industrial environment. This testing space includes areas under line-of-sight (LOS) and diverse non-LOS conditions caused by the reflection, propagation, and the diffraction of the UWB radio signals across different obstacles. The study also includes the analysis of the estimated azimuth and elevation angles for the Ubisense system, which is the only one that incorporates this feature using an array antenna at each sensor. Finally, we analyze the 3-D positioning estimation performance of the three UWB systems using a Bayesian filter implemented with a particle filter and a measurement model that takes into account bad range measurements and outliers. A final conclusion is drawn about which system performs better under these industrial conditions.

Comparing Ubisense, BeSpoon, and DecaWave UWB Location Systems: Indoor Performance Analysis

In recent years, unmanned aerial vehicles (UAVs) have received considerable attention from regulators, industry and research community, due to rapid growth in a broad range of applications. Particularly, UAVs are being used to provide a promising solution to reliable and cost-effective wireless communications from the sky. The deployment of UAVs has been regarded as an alternative complement of existing cellular systems, to achieve higher transmission efficiency with enhanced coverage and capacity. However, heavily utilized microwave spectrum bands below 6 GHz utilized by legacy wireless systems are insufficient to attain remarkable data rate enhancement for numerous emerging applications. To resolve the spectrum crunch crisis and satisfy the requirements of 5G and beyond mobile communications, one potential solution is to use the abundance of unoccupied bandwidth available at millimeter wave (mmWave) frequencies. Inspired by the technique potentials, mmWave communications have also paved the way into the widespread use of UAVs to assist wireless networks for future 5G and beyond wireless applications. In this paper, we provide a comprehensive survey on current achievements in the integration of 5G mmWave communications into UAV-assisted wireless networks. More precisely, a taxonomy to classify the existing research issues is presented, by considering seven cutting-edge solutions. Subsequently, we provide a brief overview of 5G mmWave communications for UAV-assisted wireless networks from two aspects, i.e., key technical advantages and challenges as well as potential applications. Based on the proposed taxonomy, we further discuss in detail the state-of-the-art issues, solutions, and open challenges for this newly emerging area. Lastly, we complete this survey by pointing out open issues and shedding new light on future directions for further research on this area.

/pdf/a-survey-on-5g-millimeter-wave-communications-for-uav-1ex6lnjkdj.pdf

A Survey on 5G Millimeter Wave Communications for UAV-Assisted Wireless Networks

Visual inspection has traditionally been used for structural health monitoring. However, assessments conducted by trained inspectors or using contact sensors on structures for monitoring a...

Autonomous UAVs for Structural Health Monitoring Using Deep Learning and an Ultrasonic Beacon System with Geo‐Tagging

Cybersecurity challenges in vehicular communications

Commonly used unmanned aerial vehicle (UAV) platforms rely on the use of global navigation satellite system (GNSS) receivers for navigation. To enable the autonomous navigation of cooperative UAVs in GNSS-denied environments, the use of an ultra-wideband (UWB) positioning system is proposed. This paper discusses the design and evaluation of a practical and cooperative UWB positioning system using newly available integrated radio frequency hardware and antennas. Constellation-aware parameters, as well as other effects like antenna characteristics, are taken into consideration. A non-line-of-sight rejection is implemented based on the ratio of the first path compared to the power of the cumulated channel impulse response. An experiment covering a range of positions and orientations is conducted to gain a broad, representative set of results to assess the system accuracy in real-life usage. In a first experiment the system performance achieves a root-mean-square error of under 10 cm in the horizontal plane and under 20 cm in the three-dimensional space with a probability of 95 %. A GNSS emulation system is implemented to evaluate the real-time in-flight use of the UWB positioning system on an experimental UAV carrier. A proof of concept is given that the GNSS emulation may be used with commercially available UAV platforms to augment those systems with indoor navigation capabilities.

Design of an UWB indoor-positioning system for UAV navigation in GNSS-denied environments

Ultra-wideband wireless positioning technologies based on IEEE 802.15.4a have gained attention for various use cases requiring highly precise localization. Multi-rotor unmanned aerial vehicle (UAV) systems provide several sensors for stabilization and navigation. However, absolute indoor positioning poses a problem for autonomous robotic systems. The specific challenge addressed in this paper is enabling novel applications with autonomous UAV systems through tight integration with scalable and precise receiver-side time-difference of arrival (TDOA) based ultra-wideband (UWB) indoor localization. For the in-depth validation of the proposed approach, several experiments are performed. One proves the repeatability of the proposed method by following a predefined trajectory ten times achieving close to optical motion-capture based control performance, with a 3rd quartile of the alignment error lower than 10 cm. Another experiment addresses the simultaneous flight of three UAVs in close proximity and delivers an analysis of the real-time capabilities which in turn proves the multi-user scalability. The last experiment demonstrates a user-interactive application of the proposed approach in a logistics environment. A video along with the raw samples, reference data and processed positions of the aforementioned experiments is provided alongside this work.

Scalable and precise multi-UAV indoor navigation using TDOA-based UWB localization

IEEE 802.15.4a Ultra-wideband based wireless positioning has recently gained attention for precise localization. However, the multi-user scalability of those, mostly two-way ranging based, approaches is not considered. Due to the exchange of multiple frames per ranging, two-way ranging has significant downsides in terms of scalability. This paper proposes and validates a novel approach for a multi-user time-difference of arrival based localization system using wireless clock synchronization. The system accuracy is assessed using a complex experiment, covering robotic movement and an optical reference system for comparable results. It is shown, that the accuracies achievable by time-difference of arrival positioning with wireless clock synchronization are comparable to similar two-way ranging based approaches. All raw samples, reference data and processed positions are provided alongside this work.

ATLAS - an open-source TDOA-based Ultra-wideband localization system

Current developments in unmanned aerial vehicle technology hold great potential for productive deployment in industrial cyber-physical systems While autonomous flight in outdoor environments is achieved using global navigation satellite systems, dedicated precise wireless localization is a promising candidate to enable indoor navigation However, equipping large industrial areas with wireless localization is possible, but providing the required coverage may not be economical Therefore, this work aims to augment and fuse state of the art ultra-wideband localization with monocular simultaneous localization and mapping to enable autonomous flight in areas not covered by wireless localization For the in-depth validation of the proposed approach, two experiments are performed: the first one is providing an extensive experimental analysis of the accuracy of different localization methods for drones, whereas the second experiment is showing that precise waypoint flight in areas not covered by wireless localization is feasible, lowering the threshold for integration of drone-based cyber-physical systems in current industrial environments

Enhanced UAV Indoor Navigation through SLAM-Augmented UWB Localization

Wireless positioning based on IEEE 802.15.4a has recently gained attention for precise localization. However, the multi-user scalability of those, mostly two-way ranging based, approaches is not considered. Due to the exchange of multiple frames per ranging, two-way ranging has significant downsides in terms of scalability. This paper proposes and validates a novel multi-user time-difference of arrival based localization approach using wireless clock synchronization to overcome the limitations of two-way ranging based positioning. The clock characteristics of the individual nodes are experimentally analyzed and the requirements and constraints for wireless clock synchronization are elaborated based on the experiments. The results show, that a clock synchronization rate of around 1 Hz is sufficient to achieve accuracies in the decimeter range. Experiments analyzing the multi-user capabilities of the system are conducted, highlighting the specific properties of multi-user access in the proposed time-difference of arrival based localization. The experiments show, that the system is capable of scaling gracefully under heavy load. However, clock synchronization suffers as it is degrading equally. Therefore, a novel approach is proposed and evaluated to prioritize the wireless clock synchronization to ensure load independent positioning accuracy. It is shown, that the proposed approach is capable of ensuring a synchronization receive ratio of around 90% independent of the system load.

Janis Tiemann

Papers

Design of an UWB indoor-positioning system for UAV navigation in GNSS-denied environments

Scalable and precise multi-UAV indoor navigation using TDOA-based UWB localization

ATLAS - an open-source TDOA-based Ultra-wideband localization system

Enhanced UAV Indoor Navigation through SLAM-Augmented UWB Localization

Multi-user interference and wireless clock synchronization in TDOA-based UWB localization